ترغب بنشر مسار تعليمي؟ اضغط هنا

Locality of Orthogonal Product States via Multiplied Copies

59   0   0.0 ( 0 )
 نشر من قبل Hao Shu
 تاريخ النشر 2020
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Hao Shu




اسأل ChatGPT حول البحث

In this paper, we consider the LOCC distinguishability of product states. We employ polygons to analyse orthogonal product states in any system to show that with LOCC protocols, to distinguish 7 orthogonal product states, one can exclude 4 states via a single copy. In bipartite systems, this result implies that N orthogonal product states are LOCC distinguishable if $left lceil frac {N}{4}right rceil$ copies are allowed, where $left lceil lright rceil$ for a real number $l$ means the smallest integer not less than $l$. In multipartite systems, this result implies that N orthogonal product states are LOCC distinguishable if $left lceil frac {N}{4}right rceil +1$ copies are allowed. We also give a theorem to show how many states can be excluded via a single copy if we are distinguishing n orthogonal product states by LOCC protocols in a bipartite system. Not like previous results, our result is a general result for any set of orthogonal product states in any system.

قيم البحث

اقرأ أيضاً

We study the local indistinguishability of mutually orthogonal product basis quantum states in the high-dimensional quantum system. In the quantum system of $mathbb{C}^dotimesmathbb{C}^d$, where $d$ is odd, Zhang emph{et al} have constructed $d^2$ or thogonal product basis quantum states which are locally indistinguishable in [Phys. Rev. A. {bf 90}, 022313(2014)]. We find a subset contains with $6d-9$ orthogonal product states which are still locally indistinguishable. Then we generalize our method to arbitrary bipartite quantum system $mathbb{C}^motimesmathbb{C}^n$. We present a small set with only $3(m+n)-9$ orthogonal product states and prove these states are LOCC indistinguishable. Even though these $3(m+n)-9$ product states are LOCC indistinguishable, they can be distinguished by separable measurements. This shows that separable operations are strictly stronger than the local operations and classical communication.
The general conditions for the orthogonal product states of the multi-state systems to be used in quantum key distribution (QKD) are proposed, and a novel QKD scheme with orthogonal product states in the 3x3 Hilbert space is presented. We show that t his protocol has many distinct features such as great capacity, high efficiency. The generalization to nxn systems is also discussed and a fancy limitation for the eavesdroppers success probability is reached.
We revisit the problem of detection of entanglement of an unknown two-qubit state using minimal resources. Using weak values and just two copies of an arbitrary two-qubit state, we present a protocol where a post selection measurement in the computat ional basis provides enough information to identify if the state is entangled or not. Our protocol enables complete state identification with a single-setting post selection measurement on two copies of the state. It follows that by restricting to pure states, the global interaction required for determining the weak values can be realized by local operations. We further show that our protocol is robust against errors arising from inappropriate global interactions applied during weak value determination.
The hierarchy of nonlocality and entanglement in multipartite systems is one of the fundamental problems in quantum physics. Existing studies on this topic to date were limited to the entanglement classification according to the numbers of particles enrolled. Equivalence under stochastic local operations and classical communication provides a more detailed classification, e. g. the genuine three-qubit entanglement being divided into W and GHZ classes. We construct two families of local models for the three-qubit Greenberger-Horne-Zeilinger (GHZ)-symmetric states, whose entanglement classes have a complete description. The key technology of construction the local models in this work is the GHZ symmetrization on tripartite extensions of the optimal local-hidden-state models for Bell diagonal states. Our models show that entanglement and nonlocality are inequivalent for all the entanglement classes (biseparable, W, and GHZ) in three-qubit systems.
We study thermal states of strongly interacting quantum spin chains and prove that those can be represented in terms of convex combinations of matrix product states. Apart from revealing new features of the entanglement structure of Gibbs states our results provide a theoretical justification for the use of Whites algorithm of minimally entangled typical thermal states. Furthermore, we shed new light on time dependent matrix product state algorithms which yield hydrodynamical descriptions of the underlying dynamics.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا